Organic light emitting diodes and photodetectors: Towards applications in lab-on-a-chip portable devices

We report that polymer light emitting diodes (pLEDs) and polymer photodetectors can be integrated on disposable polydimethylsiloxane [PDMS] microfluidic flowcells to form hybrid microchips for bioluminescence applications. PLEDs were successfully employed as excitation light sources for microchip based fluorescence detection of microalbuminuria (MAU), an increased urinary albumin excretion indicative of renal disease. To circumvent the use of optical filters, fluorescence was detected perpendicular to the biolabel flow direction using a CCD spectrophotometer. Prior to investigating the suitability of polymer photodiodes as integrated detectors for fluorescence detection, their sensitivity was tested with on-chip chemiluminescence. The polymer photodetector was integrated with a PDMS microfluidic flowcell to monitor peroxyoxalate based chemiluminescence (CL) reactions on the chip. This work demonstrates that our polymer photodetectors exhibit sensitivities comparable to inorganic photodiodes. Here we prove the concept that thin film solution-processed polymer light sources and photodetectors can be integrated with PDMS microfluidic channel structures to form a hybrid microchip enabling the development of disposable low-cost diagnostic devices for point-of-care analysis.